X-Sendfile

mod_xsendfile
Reference : Advanced Rails p121

The X-Sendfile protocol is a very simple standard, first introduced in the Lighttpd
web server, which directs the web server to send a file from the filesystem to the client
rather than a response generated by the application server.

X-Sendfile uses the X-Sendfile HTTPheader pointing to the server’s path to the file
to send, in conjunction with the other standard HTTPheaders. A typical response
using X-Sendfile would look something like this:
X-Sendfile: /home/rails/sample_application/private/secret_codes_69843.zip<br />Content-Type: application/octet-stream<br />Content-Disposition: attachment; file="secret_codes.zip"<br />Content-Length: 654685<br />Assuming the web server is properly

From Rails, you can set the response headers by modifying the response.headers
hash:<br />response.headers['X-Sendfile'] = file_path<br />response.headers['Content-Type'] = 'application/octet-stream'<br />response.headers['Content-Disposition'] = "attachment; file=\"#{file_name}\""<br />response.headers['Content-Length'] = File.size(file_path)